The USAF’s F-22 Raptor has been on stand down for few months now. The stand down was to investigate any potential issues with the aircraft’s onboard oxygen generation system for use at high altitudes. The investigation was started after pilots were experiencing symptoms of hypoxia during flights in the aircraft.

The chief of the USAF will get options this week on how to lift the grounding of the F-22 and allow the aircraft and its pilots to return to the skies. In the cases of the hypoxia-like symptoms, the pilots were also found to have toxins in the bloodstream. USAF chief Gen. Norton Schwartz said last week that the full report would allow him to decide what restrictions to place on the return to operating for the F-22.

There had been previous discussions that one of the potential restrictions would be to limit the F-22 to an operational altitude of 40,000 feet until the issue was pinpointed. Others want the aircraft to return to the 60,000 ceiling right away. One of the reasons a fix for the F-22 issue hasn't been found according to some is that the Air Force physiologists that are working on the problem don’t have practical experience. 

The operational F-22 community wants someone with hands-on experience with the aircraft to be part of the process. Specifically, they are calling for Kevin Divers to join the team. Divers is a former pilot who later trained to be a physiologist, and now runs a consulting firm called Warrior Edge. Divers was part of the F-22 Combines Test Force during the development of the aircraft.

Divers said during his time in the USAF, "The trend that I saw, as rated-physiologists left the career field, is that the aerospace physiology officer leans more on academic knowledge." He continued, "There is a major gap between research and operational knowledge of the F-22 that could be causing this delay."

Divers added, "I know all of their [F-22] flight equipment - the [onboard oxygen generating system] OBOGS, the entire plumbing of the aircraft to the OBOGS - because I had to study it and look at it from the safety standpoint for the pilots. My pilot training experience taught me to break down subsystems and know the aircraft to the level that the aircrew has to know it. Air Force physiologists aren't trained that way coming into the Air Force."

While the fate of the F-22 should be decided shortly, another investigation into the F-22 and a crash that killed one pilot has been concluded according to sources. In November of 2010, a USAF F-22 piloted by Capt. Jeff "Bong" Haney crashed in Alaska. The pilot was killed in the crash. The cause has been under investigation and the industry source claims that the crash was caused by a malfunction in the F-22 engine's air bleed system. 

Defense News claims that the same information was confirmed by another source, this one a pilot. According to an accident report, the bleed air issue caused the F-22 environmental control system and the onboard oxygen generation system to shut down. However, the USAF refutes these sources.

Air Force spokesman Lt. Col. John Dorrian wrote in an email to Defense News, "The information provided by your 'industry source' is not a wholly accurate characterization of the crash. However, due to the ongoing Accident Investigation Board process I am not able to provide point-by-point confirmation, as the information is not yet releasable. PACAF is conducting the AIB process and will release appropriate information once the process is complete."

The source claims that he doesn’t see how the OBOGS that has caused the F-22 fleet grounding could have been ruled out as the cause for the crash.